The social network, Friends Reunited, is set to close after 15 years of being online.
Steve Pankhurst, one of the site's early founders, said in an email that the site was "no longer used for the purpose it was built for".
In the wake of the announcement, he appeared to be surprised over Twitter's interest as the topic started trending.
According to PA, Pankhurst said: "I knew it was near impossible to reboot something that was old and in decline."
Launching in 2000, it was bought by ITV for £175million five years later. Despite racking up more than 10 million registered users, the network failed to keep up with new social media sites such as Facebook and Twitter.
"And I also realised that of the more than 10m users registered, a lot had done so over a decade ago and hence their contact details were out of date," Pankhurst wrote.
Those who remembered Friends Reunited tweeted their surprise over how long it has taken for the site to close.
Others took the opportunity to bid farewell while few questioned whether the same demise would follow similar networking sites.